1. Field of the Invention
The invention relates to a rotor of an electric machine, in particular a turbo-generator, having an exciting current supply lead for connecting the exciter lead, which extends axially in the center of the rotor, to the exciter winding conductors in the winding overhang of the rotor, which rotor has a rotor cap for supporting the winding overhang of the exciter winding, having an exciter terminal stud made from steel, which is arranged in a radial shaft bore-hole an is connected electrically and mechanically at its inner end to the said exciter lead and is connected electrically and mechanically at its outer end outside the rotor shaft via connecting conductors to the conductors of the rotor winding overhang, and having means for supporting the said connecting conductors.
The invention refers in this connection t the prior art which emerges, for example, from U.S. Pat. 3,733,502.
2. Discussion of Background
In turbo-generators, the guidance of the exciter leads on the rotor to the rotor winding is generally performed in a central shaft bore-hole. The conductors in the shaft bore-hole are mostly solid and insulated all around. Terminal studs are screwed into these solid conductors. A lead is then guided firstly axially from the radially outer end of the studs, and then radially to the exciter winding termination in the rotor winding overhang. In operation this lead is extremely highly stressed as a consequence of the shaft deflection due to the dead weight of the rotor and to unbalance forces.
Thus, in an electric machine according to U.S. Pat. No. 3,733,502 the axial section of this lead is laid in a slot which is sealed by means of slot wedges having a trapezoidal cross section (cf. FIG. 7 there). In order to reduce effects on the radially extending section of the supply leads, the latter extend virtually entirely in the rotor forging.
In German Offenlegungsschrift 2,362,886, the axial conductor sections extend in slots similar to U.S. Pat. No. 3,733,502. There, however, the transition point from the axial to the radial section is formed by separate support elements having rounded edges.
In addition to centrifugal forces, the axially extending lead sections and the associated fixing wedges are also acted upon, in particular, by relative movements between the bolt end and the exciter winding termination in the rotor winding overhang. In the most unfavorable case, it is possible as a result for fatigue cracks which can lead to damage to form in the region of the wedge bearing surfaces in the slots.
It is disadvantageous in all known embodiments that the replacement of the power supply conductors is very expensive.